linagliptin add-on to insulin background therapy

Conditions: Diabetes Mellitus, Type 2

Summary: to evaluate the efficacy and safety of linagliptin compared to placebo when added on to insulin therapy alone or in combination with metformin in chinese patients with type 2 diabetes mellitus with insufficient glycaemic control


Eligibility criteria:
inclusion criteria: * diagnosis of type 2 diabetes mellitus prior to informed consent. * chinese male or female patients who are pre-treated with insulin alone or in combination with metformin: * with maximum insulin dose of \<= 1 unit/kg/day. acceptable basal insulins could be insulin glargin, insulin detemir or nph (neutral protamin hagedorn) insulin with duration of action up to 24 h; acceptable pre-mixed insulins could be preparations with 25/75 or 30/70 ratio, with once or twice daily posology only. the total insulin dose should not be changed by more than 10% of the baseline value within the 12 weeks prior to randomisation (visit 3). both human insulin \& insulin analogue are accepted. * if the patient is taking metformin, stable dose (at least 1500 mg daily) must be maintained for at least 12 weeks without dose adjustments prior to randomisation (visit 3). * hba1c fulfills the following criteria: \>= 7.5 % to \<= 10.0 % at visit 1. * age \>= 18 years at visit 1. * bmi \<= 45 kg/m2 (body mass index) at visit 1. * women of childbearing potential must be ready and able to use highly effective methods of birth control per ich (international conference on harmonisation) m3 (r2) that result in a low failure rate of less than 1% per year when used consistently and correctly. a list of contraception methods meeting these criteria is provided in the patient information. * a woman is considered of childbearing potential (wocbp), i.e. fertile, following menarche and until becoming post-menopausal unless permanently sterile. * permanent sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy. * signed and dated written informed consent by date of visit 1 in accordance with ich-gcp (good clinical practice) and local legislation exclusion criteria: * uncontrolled hyperglycaemic with a glucose level \>240 mg/dl (\>13.3 mmol/l) after an overnight fast during placebo run-in and confirmed by a second measurement (not on the same day). * any other antidiabetic drug within 3 months prior to informed consent except those defined as background treatment via inclusion criterion 2. * acute coronary syndrome (non-stemi (st segment elevation myocardial infarction), stemi and unstable angina pectoris), stroke or tia (transient ischemic attack) within 3 months prior to informed consent. * indication of liver disease, defined by serum levels of either alt (alanine aminotransferase) (sgpt (serum glutamic pyruvate transaminase )), ast (aspartate aminotransferase) (sgot (serum glutamic-oxaloacetic transaminase)), or alkaline phosphatase above 3 × upper limit of normal (uln (upper limit of normal)) as determined during screening and/or run-in phase. * any contraindications to metformin according to the local label for those patients that enter the study with metformin therapy as provided in isf (investigator site file). * bariatric surgery within the past two years and other gastrointestinal surgeries that induce chronic malabsorption. * medical history of cancer (except for basal cell carcinoma) and/or treatment for cancer within the last 5 years. * blood dyscrasias or any disorders causing hemolysis or unstable red blood cell (e.g. malaria, babesiosis, haemolytic anemia). * known hypersensitivity or allergy to the investigational product or its recipients. * treatment with anti-obesity drugs 3 months prior to informed consent or any other treatment at the time of screening (i.e. surgery, aggressive diet regimen, etc.) leading to unstable body weight. * current treatment with systemic steroids at time of informed consent or change in dosage of thyroid hormones within 6 weeks prior to informed consent or any other uncontrolled endocrine disorder except t2dm (type 2 diabetes mellitus). * women who are pregnant, nursing, or who plan to become pregnant while in the trial. * alcohol or drug abuse within the 3 months prior to informed consent that would interfere with trial participation or any ongoing condition leading to a decreased compliance to study procedures or study drug intake in the opinion of the investigator. * participation in another trial with an investigational drug within 2 months prior to informed consent or previous enrolment in this trial. * any other clinical condition that would jeopardize patient's safety while participating in this clinical trial in the opinion of the investigator.